Method and system for attaching a graft to a blood vessel

ABSTRACT

Anastomotic stents for connecting a graft vessel to a target vessel, and methods of use thereof. The anastomotic stents of the invention are suitable for use in a variety of anastomosis procedures, including coronary artery bypass grafting. One embodiment of the invention comprises a large vessel anastomotic stent for use with large diameter target vessels such as the aorta or its major side branches. Another embodiment of the invention comprises a small vessel anastomotic stent for use on a target vessel which has a small diameter such as a coronary artery. Another aspect of the invention involves applicators for use with the stents of the invention.

BACKGROUND OF THE INVENTION

[0001] This invention generally relates to devices and methods forperforming a vascular anastomosis, and more particularly to stents forsecuring a graft vessel to a target vessel.

[0002] Vascular anastomoses, in which two vessels within a patient aresurgically joined together to form a continuous channel, are requiredfor a variety of conditions including coronary artery disease, diseasesof the great and peripheral vessels, organ transplantation, and trauma.For example, in coronary artery disease (CAD), an occlusion or stenosisin a coronary artery interferes with blood flow to the heart muscle. Inorder to restore adequate blood flow to the heart, a graft vessel in theform of a prosthesis or harvested artery or vein is used to rerouteblood flow around the occlusion. The treatment, known as coronary arterybypass grafting (CABG), can be highly traumatic to the patient's system.

[0003] In conventional CABG a large incision is made in the chest andthe sternum is sawed in half to allow access to the heart. In addition,cardiopulmonary bypass, in which the patient's blood is circulatedoutside of the body through a heart-lung machine, is used so that theheart can be stopped and the anastomosis performed. In order to minimizethe trauma to the patient's system induced by conventional CABG, lessinvasive techniques have been developed in which the surgery isperformed through small incisions in the patient's chest with the aid ofvisualizing scopes. Less invasive CABG can be performed on a beating ora non-beating heart and thus may avoid the need for cardiopulmonarybypass.

[0004] In both conventional and less invasive CABG, the surgeon has tosuture the graft vessel in place between the coronary artery and a bloodsupplying vein or artery. The suturing procedure is a time consuming,difficult process requiring a high level of surgical skill. In order toperform the suturing procedure, the surgeon must have relativelyunobstructed access to the anastomotic site within the patient. As aresult, in less invasive approaches which provide only limited access tothe patient's vessels, some of the major coronary vessels cannot bereached adequately, which can result in incomplete revascularization anda resulting negative effect on patient survival. Moreover, certaintarget vessels, such as heavily calcified coronary vessels, vesselshaving a very small diameter of less than about 1 mm, and previouslybypassed vessels, may make the suturing process difficult or impossible,so that a sutured anastomosis is not possible.

[0005] Additionally, a common problem with CABG has been the formationof thrombi and atherosclerotic lesions at and around the grafted artery,which can result in the reoccurrence of ischemia. Moreover, secondoperations necessitated by the reoccurrence of arterial occlusions aretechnically more difficult and risky due to the presence of the initialbypass. For example, surgeons have found it difficult to saw the sternumin half during the next operation without damaging the graft vesselsfrom the first bypass which are positioned behind the sternum.

[0006] Therefore, it would be a significant advance to provide asutureless vascular anastomosis in which the graft vessels can bepositioned on a variety of locations on target vessels having a varietyof different diameters, which is easily performed, and which minimizesthrombosis associated with the anastomosis. The present inventionsatisfies these and other needs.

SUMMARY OF THE INVENTION

[0007] The invention is directed to anastomotic stents for connecting agraft vessel to a target vessel, and methods of use thereof. Theanastomotic stents of the invention are suitable for use in a variety ofanastomosis procedures, including coronary artery bypass grafting. Theterm “target vessel” refers to vessels within the patient which areconnected to either or both of the upstream and the downstream end ofthe graft vessel. One embodiment of the invention comprises a largevessel anastomotic stent for use with large diameter target vessels suchas the aorta or its major side branches. Another embodiment of theinvention comprises a small vessel anastomotic stent for use on a targetvessel which has a small diameter such as a coronary artery. Anotheraspect of the invention involves applicators for use with the stents ofthe invention. The terms “distal” and “proximal” as used herein refer topositions on the stents or applicators relative to the physician. Thus,the distal end of the stent is further from the physician than is thestent proximal end. The proximal end of an implanted stent is furtherfrom the center of the target vessel lumen than is the stent distal end.

[0008] The large vessel anastomotic stents of the invention generallycomprise a substantially cylindrical body having a longitudinal axis, anopen proximal end, an open distal end, a lumen therein, and at least onedeformable section which radially expands to form a flange. The stent,with one end of a graft vessel attached thereto, is inserted into anincision in a wall of the target vessel with the deformable section in afirst configuration, and the deformable section is radially expanded toa second configuration to deploy the flange. The flange applies an axialforce, substantially aligned with the stent longitudinal axis, againstthe wall of the target vessel. Additionally, the flange is configured toapply a radial force, substantially transverse to the stent longitudinalaxis, against the wall of the target vessel, to secure the stent to thetarget vessel.

[0009] In one embodiment of the large vessel stent, the stent has asingle deformable section forming a flange, preferably on a distalsection of the stent. However, a plurality of deformable sections may beprovided on the stent. For example, in an alternative embodiment, thestent has a second deformable section on a proximal section of thestent. With the proximal and distal end flanges deployed, the stent isprevented from shifting proximally out of the target vessel or distallyfurther into the interior of the target vessel.

[0010] The large vessel stents of the invention are configured toconnect to target vessels of various sizes having a wall thickness of atleast about 0.5 mm, and typically about 0.5 mm to about 5 mm. In oneembodiment of the invention, the large vessel anastomotic stent isconfigured to longitudinally collapse as the deformable section isradially expanded. The surgeon can control the longitudinal collapse tothereby position the distal end flange at a desired location at leastpartially within the incision in the target vessel wall. Moreover, inthe embodiment having a proximal end flange, the surgeon can control theposition of the proximal end flange by longitudinally collapsing thestent to a greater or lesser degree, to thereby position the proximalend flange at a desired location in contact with the target vessel.Thus, regardless of the thickness of the target vessel wall, the stentcan be longitudinally collapsed to position the flanges against thetarget vessel wall and effectively connect the stent thereto. Thisfeature is significant because the stent must be connected to targetvessels which have a wide range of wall thickness. For example, theaortic wall thickness is typically about 1.4 mm to about 4.0 mm.Therefore, regardless of the thickness of the target vessel wall, thedegree of deployment of the proximal end flange, and thus thelongitudinal collapse of the stent, can be controlled by the physicianto thereby effectively connect the stent to the target vessel. Forexample, the surgeon may choose between partially deploying the proximalend flange so that it is positioned against an outer surface of thetarget vessel wall, or fully deploying the flange to position it incontact with the media of the target vessel wall within the incision inthe target vessel wall.

[0011] In a presently preferred embodiment, the graft vessel is attachedto the stent before insertion into the patient by placing the graftvessel within the lumen of the stent, and everting the end of the graftvessel out the stent distal end and about at least the distal deformablesection. In a presently preferred embodiment, the graft vessel iseverted about at least the section which contacts the media of thetarget vessel wall proximal to the distal deformable section, tofacilitate sealing at the anastomosis site.

[0012] In a presently preferred embodiment of the invention, thedeformable section on the large vessel stent comprises a plurality ofhelical members interconnected and disposed circumferentially around thestent. By rotating the distal end and the proximal end of the stentrelative to one another, the helical members radially expand and thestent longitudinally collapses to form the flange. In a presentlypreferred embodiment, the distal flange is configured to deploy beforethe proximal end flange.

[0013] Another aspect of the invention comprises the applicatorsdesigned for introducing and securing the large vessel anastomoticstents of the invention to the target vessel. One such applicator isconfigured to apply torque and axial compressive load to the largevessel stent, to thereby radially expand the deformable section whichforms the flange. The applicator of the invention may be provided with asharp distal end, to form an incision in the target vessel wall throughwhich the stent is inserted or to otherwise facilitate insertion of thestent into the target vessel wall. Another embodiment of the applicatorof the invention includes a catheter member having one or moreinflatable members designed to expand the incision in the target vesseland introduce the large vessel stent therein.

[0014] Another embodiment of the invention comprises small vesselanastomotic stents for use on small target vessels such as coronaryarteries. The small vessel stents generally comprise an outer flangeconfigured to be positioned adjacent an outer surface of the targetvessel, and an inner flange configured to be positioned against an innersurface of the target vessel and connected to the outer flange. Theouter and inner flanges generally comprise a body defining an opening,with one end of the graft vessel secured to the outer flange.

[0015] The small vessel anastomotic stents of the invention are used onsmall target vessels having a wall thickness of less than about 1.0 mm,and typically about 0.1 mm to about 1 mm. For example, small targetvessels include coronary arteries. Despite the small size of the targetvessels, the small vessel stents of the invention provide suturelessconnection without significantly occluding the small inner lumen of thetarget vessel or impeding the blood flow therethrough.

[0016] In a presently preferred embodiment of the invention, the graftvessel is received into the opening in the outer flange and evertedaround the body of the outer flange to connect to the outer flange. Inanother embodiment, as for example when the graft vessel is a mammaryartery, the graft vessel is connected to the outer flange by connectingmembers such as sutures, clips, hooks, and the like.

[0017] The outer flange, with the graft vessel connected thereto, isloosely connected to the inner flange before insertion into the patient.The space between the loosely connected inner and outer flanges is atleast as great as the wall thickness of the target vessel so that theinner flange can be inserted through an incision in the target vesseland into the target vessel lumen, with the outer flange outside thetarget vessel. With the outer and inner flanges in place on either sideof a wall of the target vessel, tightening the flanges togethercompresses a surface of the graft vessel against the outer surface ofthe target vessel. This configuration forms a continuous channel betweenthe graft vessel and the target vessel, without the need to suture thegraft vessel to the target vessel wall and preferably without the use ofhooks or barbs which puncture the target vessel.

[0018] In one embodiment of the invention, the inner flange isintroduced into the target vessel in a folded configuration andthereafter unfolded into an expanded configuration inside the targetvessel. The folded configuration reduces the size of the inner flange sothat the size of the incision in the target vessel wall can beminimized. Folding the flange minimizes trauma to the target vessel andrestenosis, and facilitates sealing between the graft and target vesselat the anastomotic site.

[0019] In a presently preferred embodiment of the invention, the innerand outer flanges are connected together by prongs on one memberconfigured to extend through the body of the other member. However, theinner and outer flanges may be connected together by a variety ofdifferent types of connecting members such as sutures, hooks, clips, andthe like. In a presently preferred embodiment, the flange members areconnected together by prongs on the inner member configured to extendthrough the incision in the target vessel wall, without puncturing thewall of the target vessel, and through prong receiving openings in thebody of the outer flange. The prong receiving openings in the outerflange may be configured to allow for the forward movement of the prongthrough the opening to bring the inner and outer flanges together, butprevent the backward movement of the prong out of the opening, so thatthe inner and outer flanges remain substantially compressed together toseal the anastomotic site.

[0020] Another aspect of the invention comprises a small vessel stentapplicator which facilitates introduction of the inner flange into thetarget vessel lumen, and connection of the inner flange to the outerflange around the target vessel. In one embodiment of the small vesselstent applicator, the applicator folds the inner flange into the foldedconfiguration for introduction into the lumen of the target vessel.

[0021] Anastomotic systems of the invention may comprise combinations ofthe large and small vessel stents of the invention, for connecting oneor both ends of a graft vessel to target vessels. Typically, in acoronary bypass using the anastomotic system of the invention, a largevessel stent connects the proximal end of the graft vessel to the aorta,and a small vessel stent connects the distal end of the graft vessel toan occluded coronary artery. However, it will be apparent to one ofordinary skill in the art that various combinations and uses of theanastomotic stents of the invention may be used. For example, inpatients with an extreme arteriosclerotic lesion in the aorta, which mayresult in serious complications during surgical procedures on the aorta,the anastomotic stents of the invention allow the surgeon to avoid thisregion and connect the proximal end of the graft vessel to any otheradjacent less diseased vessel, such as the arteries leading to the armsor head.

[0022] The large and small vessel stents of the invention are providedin a range of sizes for use on various sized graft vessels. Thus, theanastomotic stents of the invention can be used with venous grafts, suchas a harvested saphenous vein graft, arterial grafts, such as adissected mammary artery, or a synthetic prosthesis, as required.

[0023] Connection of the large vessel stent does not require thestoppage of blood flow in the target vessel. Moreover, the anastomoticstents of the invention can be connected to the target vessel withoutthe use of cardiopulmonary bypass. Additionally, the surgeon does notneed significant room inside the patient to connect the anastomoticstents of the invention to the target vessel. For, example, unlikesutured anastomoses which require significant access to the aorta forthe surgeon to suture the graft vessel thereto, the anastomotic stentsof the invention allow the proximal end of the graft vessel to beconnected to any part of the aorta. All parts of the aorta areaccessible to the large vessel stents of the invention, even whenminimally invasive procedures are used. Consequently, the graft vesselmay be connected to the descending aorta, so that the graft vessel wouldnot be threatened by damage during a conventional sternotomy if a secondoperation is required at a later time.

[0024] The anastomotic stents of the invention provide a suturelessconnection between a graft and a target vessel, while minimizingthrombosis or restenosis associated with the anastomosis. Theanastomotic stents can be attached to the target vessel inside a patientremotely from outside the patient using specially designed applicators,so that the stents are particularly suitable for use in minimallyinvasive surgical procedures where access to the anastomosis site islimited. The stents of the invention allow the anastomosis to beperformed very rapidly, with high reproducibility and reliability, andwith or without the use of cardiopulmonary bypass.

[0025] These and other advantages of the invention will become moreapparent from the following detailed description of the invention andthe accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is an elevational view, partially in phantom and insection, of a small vessel stent of the invention, with a graft vessel,partially in section and broken away, connected thereto, positioned in atarget vessel.

[0027]FIG. 2 is a transverse cross sectional view of the small vesselstent, together with the graft and target vessel, shown in FIG. 1, takenalong lines 2-2.

[0028]FIG. 3 is an exploded view of the graft vessel, the small vesselstent with the inner and outer flanges, and the graft vesseldisconnected.

[0029]FIG. 4. is an elevational view, partially in phantom, of the smallvessel stent shown in FIG. 3, with the outer flange and the graftvessel, partially broken away, connected thereto, and with the innerflange in the target vessel lumen.

[0030]FIG. 5 is an elevational view of the small vessel stent shown inFIG. 4, connected to the target vessel.

[0031]FIG. 6 is an elevational view of a prong and a prong receivingopening, on the outer flange which embodies features of the invention.

[0032]FIG. 7 is an elevational view, partially in section, of a smallvessel stent with the inner flange folded for insertion into the targetvessel, with the short dimension sides folded inward, and with the graftvessel, partially broken away.

[0033]FIG. 8 is an elevational view, partially in section, of a smallvessel stent with the inner flange folded for insertion into the targetvessel, with the short dimension sides and the long dimension sidesfolded inward, and with the graft vessel, partially broken away.

[0034]FIG. 9 is an elevational view of an compressible small vesselstent inner flange in a partially compressed configuration.

[0035]FIG. 10 is an elevational view, partially in section, of a smallvessel stent applicator which embodies features of the invention.

[0036]FIG. 11 is a longitudinal cross sectional view of the applicatorshown in FIG. 10 with a small vessel stent therein, in position in atarget vessel.

[0037]FIG. 12 is an elevational, exploded view of a graft vessel, alarge vessel anastomotic stent of the invention with the deformablesections in the first configuration, and a target vessel.

[0038]FIG. 13 is a transverse cross sectional view of the large vesselstent shown in FIG. 12, taken along lines 13-13.

[0039]FIG. 14 is an flattened view of a large vessel anastomotic stentof the invention with the deformable sections in the firstconfiguration.

[0040]FIG. 15 is an elevational view of a large vessel anastomotic stentof the invention with the distal deformable section in the secondconfiguration.

[0041]FIG. 16 is a transverse cross sectional view of the large vesselstent shown in FIG. 15, taken along lines 16-16.

[0042]FIG. 17 is an elevational view, partially in section and Tokenaway, of the large vessel stent shown in FIG. 12, with an everted graftvessel thereon, and a target vessel.

[0043]FIG. 18 is a longitudinal cross-sectional view of the large vesselstent and graft vessel thereon in a target vessel.

[0044]FIG. 19 is a longitudinal cross-sectional view of the large vesselstent shown in FIG. 18, with the distal end deformable section in thesecond configuration.

[0045]FIG. 20 is a longitudinal cross-sectional view of the large vesselstent shown in FIG. 19, with the proximal end deformable section in thesecond configuration.

[0046]FIG. 21 is a flattened view of an alternative embodiment of thelarge vessel anastomotic stent of the invention having voids in thebody.

[0047]FIG. 22 is a flattened view of an alternative embodiment of thelarge vessel anastomotic stent of the invention having a curvilineardistal end.

[0048]FIG. 23 is an elevational view of a large vessel stent applicatorwhich embodies features of the invention.

[0049]FIG. 24 is a transverse cross sectional view, partially in sectionand broken away of the distal end of an applicator with a large vesselstent and graft vessel thereon, with a vessel penetrating membertherein.

[0050]FIGS. 25 and 26 are transverse cross sectional views of theapplicator assembly shown in FIG. 24 taken along lines 25-25 and 26-26,respectively.

[0051]FIG. 27 is an elevational view of the distal end of the applicatorshown in FIG. 23.

[0052] FIGS. 28A-28H are elevational views, partially in section, of theapplicator, and large vessel stent and vessel penetrating member thereinduring connection of the large vessel stent to a target vessel.

[0053]FIG. 29 is an transverse cross sectional view of an alternativeembodiment of the large vessel stent having a distal flange angledtoward the distal end of the stent.

[0054]FIG. 30 is an elevational view of a human heart having a graftvessel attached thereto.

DETAILED DESCRIPTION OF THE INVENTION

[0055] A presently preferred embodiment of the small vessel stent 10 ofthe invention, for connecting one end of a graft vessel to a smalltarget vessel, is illustrated in FIG. 1. The small vessel stent 10comprises an outer flange 11 having a body 12 which defines an opening13 configured to receive the end of the graft vessel 21, and an innerflange 14 having a body 15 which defines an opening 16. The inner flangeis configured to be connected to the outer flange, with the openings 13,16 at least in part aligned. In the embodiment illustrated in FIG. 1,prongs 17 on the inner flange are configured to be received within smallopenings 18 in the outer flange, to thereby connect the flangestogether. As best illustrated in FIG. 2, showing a transverse crosssection of the small vessel stent 10 shown in FIG. 1, taken along lines2-2, the inner flange 14 is configured to be positioned within a lumen23 of the target vessel 22 against an inner surface 24 of the targetvessel, and the outer flange 11 is configured to be positioned againstan outer surface 25 of the target vessel 22. In the embodimentillustrated in FIGS. 1 and 2, the inner and outer flanges have an arcedconfiguration to facilitate positioning against the arced surface of thetubular vessel. The small vessel stent 10 is preferably used with smalltarget vessels, such as arteries, which typically have thin walls andsmall inner diameters.

[0056] In the embodiment illustrated in FIG. 1, the inner and outerflanges have a short dimension and a long dimension, i.e. aresubstantially oblong. The graft receiving opening 13 in the outerflange, and the opening 16 in the inner flange, are also substantiallyoblong.

[0057]FIG. 3 is an exploded view of the inner flange 14, outer flange11, and a graft vessel 21, at an incision 26 in the target vessel 22. InFIG. 4, the graft vessel has been connected to the outer flange byinserting the end of the graft vessel through the graft receivingopening 13, and everting the graft end over the outer flange.Additionally, connecting members such as sutures, hooks or clips may beused to fix the graft vessel to the outer tubular member (not shown).The prongs 17 on the inner flange pierce through the wall of the graftvessel and then through the small openings 18 in the outer flange. FIG.4 illustrates the inner and outer flanges loosely connected together forpositioning at the target vessel, with only a partial length of theprongs 17 inserted through the prong receiving opening 18, before theflanges are tightened down around the wall of the target vessel.

[0058] With the outer flange 11 connected to the graft vessel 21 and theinner flange 14 connected to the outer flange 11, the inner flange isintroduced into the incision 26 in the target vessel 22, and the innerand outer flanges are tightened together so that a compressive force isapplied to the graft vessel against the outer surface 25 of the targetvessel. Thus, the anastomosis channel is formed from the target vessellumen, through opening in the inner flange, and into the graft vessellumen. After the inner and outer flanges are tightened around the wallof the target vessel, in the embodiment having prongs 17, a length ofthe prongs extending above the target vessel can be broken off orotherwise removed. FIG. 5 is an elevational view of the small vesselstent shown in FIG. 4, connected to the target vessel, with a length ofthe free ends of the prongs 17 removed.

[0059] In one embodiment of the invention, the prongs 17 on the innerflange and the prong receiving openings 18 on the outer flange areconfigured to fixedly mate together. FIG. 6 illustrates one embodimentof the prong 17 and prong receiving openings 18. The opening 18 hasdeflectable tabs 19 which deflect to allow displacement of the prong 17longitudinally into the opening from the under side of the outer flangeto the upper side of the outer flange, but which wedge against the prongto prevent the inserted prong from moving out of the opening 18 from theupper side to the under side of the outer flange. Additionally, a quickrelease (not shown) may be provided on the prongs to allow the prongswhich are only partially inserted through the prong receiving opening tobe quickly released therefrom in the event of an aborted procedure.

[0060] In a presently preferred embodiment of the small vessel stent,the inner flange has a folded configuration having a reduced profile tofacilitate insertion into the incision in the target vessel. In oneembodiment, the length of the stent is shortened by flexing the shortdimensioned sides of the stent together, as illustrated in FIG. 7. Tohold the inner flange in the folded configuration for insertion into thetarget vessel, a pair of inwardly tensioned arms 43, preferably as apart of an applicator, are used in one embodiment of the invention.Additionally, the width of the stent can be shortened by flexing thelong dimensioned sides of the stent together, as illustrated in FIG. 8.In the presently preferred embodiment of the folding inner flangeillustrated in FIG. 7 and 8, the inner flange is formed from asuperelastic or pseudoelastic material, such as a NiTi alloy, tofacilitate folding the inner flange and to provide improved sealingagainst the wall of the target vessel after the inner flange is unfoldedinside the target vessel lumen. However, other configurations may beused, as for example, an inner flange having a collapsible section. Forexample, FIG. 9 illustrates an inner flange having a collapsible section27 on the long dimensioned sides of the inner flange, comprising aseries of short turns in alternating directions. In FIG. 9, thecollapsible section 27 is shown in a partially collapsed configurationin which the length of the inner flange is shortened by collapsing thelong dimensioned sides of the inner flange. In a presently preferredembodiment, the inner flange having a collapsible section 27 is formedof stainless steel.

[0061]FIG. 10 illustrates an applicator 31 used to position the innerflange 14 within the target vessel lumen 23, and tighten the inner andouter flanges together around the wall of the target vessel. Theapplicator 31 generally comprises a shaft 32 with proximal and distalends, a handle 33 on the proximal end, and a connecting member 34 on thedistal end for releasably attaching to the small vessel stent. In theembodiment illustrated in FIG. 9, the connecting member 34 comprises aninner compressible member 35 which is slidably insertable into an outerhousing member 36. The compressible member 35 has slots 37 configured toreceive the prongs 17 on the inner flange 14, and an opening 38configured to receive the graft vessel. The free end of the graftvessel, unconnected to the small vessel stent 10, is outside of theapplicator via the opening 38. The housing member 36 has an innerchamber 39 configured to receive the compressible member 35. The chamber39 is smaller than at least a section of the compressible member 35, tothereby compress the compressible member 35 to a smaller dimension whenit is positioned within the chamber 39. The small vessel stent isreleasably connected to the applicator, after the inner and outer flangetogether with a graft vessel are connected together, by inserting theprongs 17 on the inner flange into the slots 37. The compressible member35 clamps onto the prongs 17 as the compressible member 35 is positionedwithin the chamber 39 and the slots 37 are thereby compressed. In theembodiment illustrated in FIG. 10, the compressible member 35 ispartially out of the housing. Additionally, a connecting member (notshown) such as a clasp, clamp, or hook on the distal end of theapplicator may be used to connect the outer flange to the applicator.FIG. 10 illustrates, in an exploded view, the positioning of the innerflange 14 for releasably connecting to the applicator. Of course, asdiscussed above, the inner flange 14 is typically connected to the outerflange with a graft vessel attached thereto before being connected tothe applicator. The applicator is then used to position the stent inplace at the incision in the target vessel, with the inner flange insidethe target vessel lumen and the outer flange against the outer surfaceof the target vessel. To release the small vessel stent 10 from theapplicator, the compressible member 35 is displaced out of the housingmember 36, so that the prongs 17 are released from the slots 37 as theslots expand. In the embodiment illustrated in FIG. 10, the applicatorhas a knob 41 for turning the shaft 32 to draw the compressible member35 up into the chamber 39. The handle 33 may be used to deploy the smallvessel stent by squeezing the handle together to displace thecompressible member 35 and housing member 36 relative to one another.FIG. 11 is a longitudinal cross sectional view of an applicator as shownin FIG. 10, with a small vessel stent therein, in position at a targetvessel.

[0062] In addition, the applicator 31 may be provided with a insertionmember for holding the inner flange in the folded configurationfacilitating introduction into the target vessel lumen through theincision in the target vessel. In one embodiment, the applicatorinsertion member comprises a pair of inwardly tensioned arms 43extending past the distal end of the shaft for releasably holding theinner flange in the folded configuration, as illustrated in FIGS. 7 and8.

[0063] In the method of the invention, the small vessel stent connectsone end of a graft vessel to a target vessel to form an anastomosis. Thetarget vessel is incised, and balloons on occlusion catheters positionedagainst the target vessel are inflated to occlude blood flow upstreamand downstream of the anastomosis site. The outer flange is attached toone end of a graft vessel as described above, and, in the embodimentillustrated in FIG. 1, the prongs on the inner flange are insertedthrough the graft vessel and into the prong receiving openings in theouter flange. The graft vessel may be occluded with a temporary clamp onthe mid portion of the graft, to prevent blood loss through the graftvessel during the procedure. The inner flange is inserted into thetarget vessel lumen, and the inner and outer flanges are tightenedtogether to compress the graft vessel against the outer surface of thetarget vessel. After the inner and outer flanges are tightened together,the free end of each prong is broken off to decrease the length of theprongs left inside the patient. The prongs are typically provided with aweakened point 42 near the body of the inner flange to facilitatebreaking of the prong by tensile forces or by fatigue failure due tostrain hardening. The occlusion balloons are deflated and the occlusioncatheters removed, with the stent connected to the target vessel and thegraft vessel in fluid communication with the target vessel lumen.

[0064] In the embodiment illustrated in FIG. 1, the outer flange islonger and wider than the inner flange. The outer flange has a length ofabout 4 mm to about 12 mm, preferably about 7 mm to about 9 mm, and awidth of about 1 mm to about 5 mm. The wall thickness of the body of theouter flange is about 0.10 mm to about 0.30 mm. The inner flange has alength of about 4 mm to about 12 mm, preferably about 7 mm to about 9mm, and a width of about 0.5 mm to about 5 mm, and preferably about 2 mmto about 4 mm. The wall thickness of the body of the inner flange isabout 0.10 mm to about 0.25 mm. The inner and outer flanges arepreferably formed of stainless steel, preferably 316 stainless steel,although, as previously discussed herein, superelastic or pseudoelasticmaterials such as nickel titanium alloys, titanium, or tantalum, mayalso be used. Additionally, advanced polymers which can be plasticallydeformed, such as polyetheretherketone, may be used.

[0065]FIG. 12 illustrates a presently preferred embodiment of the largevessel stent 110 of the invention, for connecting one end of a graftvessel 125 to a large target vessel 127. The large vessel stent 110comprises a substantially cylindrical body 111 having an open proximalend 112, open distal end 113, a lumen 114 extending therein configuredto receive the end of the graft vessel 125. FIG. 13 illustrates atransverse cross section of the large vessel stent 110 shown in FIG. 12,taken along lines 13-13. FIG. 14 illustrates a flattened view of thelarge vessel stent 110 shown in FIG. 12.

[0066] The cylindrical body has a distal deformable section 115 and aproximal deformable section 116. The deformable sections 115, 116 have afirst configuration for insertion into the target vessel, and a radiallyexpanded second configuration for connecting to the target vessel. Inthe embodiment illustrated in FIG. 12, the distal and proximaldeformable sections 115, 116 comprises a plurality of helical members123, 124, respectively. In the embodiment illustrated in FIG. 12, eachhelical member has a proximal end radially spaced on the stent bodyrelative to the helical member distal end. The helical members areradially spaced around the circumference of the cylindrical body betweenlongitudinally spaced portions of the cylindrical body. In FIG. 12, thehelical members forming the deformable sections are shown in the firstconfiguration prior to being radially expanded to the secondconfiguration. As illustrated in FIG. 15, the distal deformable section115 radially expands to the second configuration to form a distal endflange 121, configured to apply a force radial to the cylindrical body111 longitudinal axis against the target vessel and thereby connect thestent to the target vessel. Similarly, the proximal deformable section116 radially expands to the second configuration to form a proximal endflange 122, as illustrated in FIG. 20. The flanges 121, 122 are deployedby circumferentially rotating the proximal end of the stent bodyrelative to the distal end of the stent body. Such rotation causes thestent body to longitudinally collapse as the helical members radiallyexpand from the first to the second configuration. FIG. 16 illustrates atransverse cross section of the large vessel stent 110 shown in FIG. 15,taken along lines 16-16.

[0067]FIG. 17 illustrates the large vessel stent shown in FIG. 12 with agraft vessel 125 attached thereto. The graft vessel is attached to thelarge vessel anastomotic stent by inserting one end of the graft vesselinto the proximal end of the cylindrical body and, in a preferredembodiment, everting the graft end 126 out the cylindrical body distalend. The graft vessel may be everted over all or only a section of theouter surface of the large vessel stent 110. In the embodimentillustrated in FIG. 17, the graft is everted over the distal deformablesection 115 which is in the first configuration prior to being radiallyexpanded to the second configuration.

[0068] FIGS. 18-20 illustrate the large vessel stent shown in FIG. 17within a wall of the target vessel 127 before and after deployment ofthe distal flange 121 and proximal flange 122. In FIG. 18, the stent hasbeen inserted into an incision in a wall of the target vessel, with thedistal end of the stent within the lumen 128 of the target vessel 127and the proximal end 112 of the stent extending outside of the targetvessel. In FIG. 19, the distal deformable section 115 has been radiallyexpanded to form the distal end flange 121. During deployment of thedistal end flange, the stent body longitudinally collapses, and thedistal end flange is positioned at least in part within the wall of thetarget vessel, so that the flange applies a force radial to the stentlongitudinal axis, illustrated by the arrow R, against the wall of thetarget vessel defining the incision therein. Additionally, an axialforce, illustrated by the arrow A, is applied against the target vesselwall, compressing the target vessel wall. The final position of thedistal end flange may vary, with the distal end flange being completelywithin the target vessel wall as shown, or, alternatively, partiallywithin the target vessel lumen (not shown). In FIG. 20, the proximaldeformable section 116 has been radially expanded to form the proximalend flange 122. The proximal end flange positioned against the outerwall of the target vessel produces an axial force, illustrated by thearrow A, against the target vessel. In the embodiment illustrated inFIG. 20, the proximal end flange is in contact with an outer surface ofthe target vessel wall. Alternatively, the proximal end flange may be incontact with the media of the target vessel between the inner and outersurface of the target vessel wall, and preferably with the proximal endof the stent flush with the outer surface of the target vessel (notshown). The degree to which flange is deployed may be varied to controlhow and where the flange contacts the target vessel wall. Thus,depending on the thickness of the target vessel wall, the proximaldeformable section can be radially expanded and longitudinally collapsedto a greater or lesser degree, so that the proximal end flange is incontact with the target vessel either on an outer surface of the targetvessel or within the incision therein in contact with the media of thetarget vessel wall.

[0069] Although the large vessel stent 110 is shown in FIG. 12 with aproximal deformable section and a distal deformable section, formingproximal and distal flanges, respectively, the large vessel stent mayhave one or more deformable sections. For example, an intermediatedeformable section (not shown) between the proximal and distal enddeformable sections may be provided for additional sealing and securingforce against the media of the target vessel wall.

[0070] In the large vessel stent illustrated in FIG. 12, theintermediate section of the body is solid. FIG. 21 illustrates analternative embodiment in which voids or openings 129 are provided inthe body wall which allow for tissue ingrowth, to thus facilitatesealing and securing of the anastomosis. In another embodiment of thelarge vessel stent, illustrated in FIG. 22, a peripheral edge on thedistal end of the large vessel stent is curvilinear, so that deploymentof the distal end flange increases the diameter of the open distal end.The generally sinusodial edge increases the diameter of the opening inthe distal end as the distal deformable section 115 is longitudinallycollapsed.

[0071] An applicator 131 is typically used to deploy the flanges andconnect the large vessel stent 110 to the target vessel 127, asillustrated in FIG. 23. In the embodiment illustrated in FIG. 23, theapplicator 131 comprises an elongated stent delivery member comprising ashaft 133 having an outer tubular member 134 having a lumen 135 therein,an inner tubular member 136 having a lumen 137 configured to receive thegraft vessel 125 and being rotatably located within the lumen of theouter tubular member, a handle 138 on the proximal end of the shaft, andconnecting members 141 on the distal end of the inner and outer tubularmembers which releasably secure the large vessel stent 110 to theapplicator 131. The distal and proximal ends of the large vessel stent110 releasably secure to the inner and outer tubular members,respectively, and the inner and outer tubular members are rotatablerelative to one another, so that the distal end of the stent can berotated relative to the proximal end of the stent and the flangesthereby deployed. In the embodiment illustrated in FIG. 23, longitudinalopenings 139, preferably coextensive with one another, in the inner andouter tubular members are provided to facilitate positioning the graftvessel, and large vessel stent connected thereto, on the applicator 131.FIG. 24 illustrates an enlarged view of the distal end of an applicatoras shown in FIG. 23, with a large vessel stent 110 and graft vessel 125thereon. FIGS. 26 and 27 illustrate transverse cross sections of theapplicator shown in FIG. 24, taken along lines 26-26 and 27-27,respectively.

[0072]FIG. 27 illustrates an enlarged view of the distal end of theapplicator 131 shown in FIG. 23. In the embodiment illustrated in FIG.27, the connecting members 141 on the outer tubular member 134 comprisetabs 142 configured to mate with slits 143, as illustrated in FIG. 12,on the proximal end of the stent. The connecting members 141 on theinner tubular member 136 comprise angular slits 144 which slidablyreceive tabs 145, as illustrated in FIG. 13 on the distal end of thestent. The tabs on the distal end of the stent are introduced into theslits on the applicator inner tubular member and a slight twistingmotion releasably secures the tabs therein. A variety of suitableconnection members can be used including releasable clamps, clips,hooks, and the like.

[0073] In one embodiment of the invention, the applicator 131 includes avessel penetrating member 146, as illustrated in FIGS. 24 and 28, forforming an incision in the target vessel. Additionally, the applicatormay be provided with one or more inflatable members for enlarging theincision, and/or drawing the applicator and stent into the incision. Forexample, in the embodiment shown in FIG. 28, a vessel penetrating member146 having proximal and distal ends, a piercing member 147 on the distalend, and at least one inflatable member on a distal section of member146, is configured to be received in the inner lumen of the innertubular member 136. In the presently preferred embodiment illustrated inFIG. 28, a proximal balloon 148, which is preferably formed fromnoncompliant material, is provided on the outer tubular member forexpanding the incision in the target vessel, and a distal balloon 151,which is preferably formed from compliant material, is provided distalto the noncompliant balloon 148, for drawing the vessel penetratingmember 146 into the target vessel lumen 128. However, the distal balloonmay be omitted and the catheter advanced through the incision and intothe target vessel lumen physically or by other suitable methods, as whenthe proximal balloon is shaped to advance into the target vessel lumenduring inflation. Additionally, the target vessel may be held to resistthe force of inserting the stent into the aortal wall, as by a suctionapplicator (not shown) positioned against an outer surface of the targetvessel, which pulls the target vessel toward the applicator.

[0074] In the method of the invention, the large vessel stent, with agraft vessel connected thereto, is introduced into the patient, insertedinto the target vessel and connected thereto by deployment of theflange. FIGS. 28A-28H illustrate the connection of the large vesselstent to a target vessel. The stent 110, with an everted graft vessel125 thereon, is releasably secured to the distal end of the applicator.The graft vessel is within the lumen of the inner tubular member, andthe vessel penetrating member 146 is within the lumen of the graftvessel 125. As shown in FIG. 28A, the applicator 131 and stent 110assembly is introduced into the patient and positioned adjacent thetarget vessel 127. An incision in the target vessel wall is formed byinserting the piercing member 147 into the targetvessel, and theincision is enlarged by inflating the proximal balloon 148 on the vesselpenetrating member 146, see FIGS. 28B and 28C. The distal end of theapplicator is then displaced distally into the target vessel lumen 128by inflating the distal balloon 151, see FIG. 28D. With the stent inposition within the incision in the target vessel, the applicator innertubular member is rotated relative to the applicator outer tubularmember, so that the distal end of the stent rotates relative to theproximal end of the stent, and the distal end flange is deployed, seeFIG. 28E. In the embodiment illustrated in FIG. 28D, the distal end ofthe stent is positioned within the target vessel lumen before the distalend flange 121 is deployed, to facilitate deployment thereof. In apresently preferred embodiment, the distal deformable section ispositioned at least in part within the target vessel lumen before thedistal flange is deployed. However, it is not required that thedeformable sections are outside of the incision in the target vesselwall for the flanges to be deployed. The proximal end flange 122 isdeployed by further rotating the applicator tubular members as outlinedabove for the distal end flange, see FIG. 28F. The balloons 148, 151 onthe vessel penetrating member 146 are then deflated and the applicator131 removed from the target vessel 127, leaving the graft vessel 125connected thereto, see FIGS. 28G and 28H.

[0075] In a presently preferred embodiment, the distal end flange isconfigured to deploy at lower torque than the proximal end flange. Adeflecting section 153 is provided on the helical members 123, 124,which bends during the deployment of the flanges. In one embodiment ofthe invention, illustrated in FIG. 14, the deflecting section 153 isformed by at least one notch in each helical member, having a depthwhich decreases the transverse dimension of the helical members at thenotch. In the embodiment of the large vessel stent illustrated in FIG.14, the a deflecting section is formed by two opposed notches 154 onopposite sides of the helical members. The notches on the distal helicalmembers have a depth that is greater than the depth of the notches onthe proximal helical members. Consequently, the transverse dimension ofthe deflecting section on the distal helical member is smaller than thatof the proximal helical members, so that the distal flange will deploybefore the proximal flange. Thus, the distal section helical membersradially expand at lower torque than the proximal helical members, sothat rotating the proximal and distal ends of the stent body relative toone another causes the distal end flange to deploy first, followed bythe proximal end flange.

[0076] In the embodiment illustrated in FIG. 14, the helical membershave deflecting sections 153 on the proximal and distal ends, and anintermediate deflecting section located substantially centrally alongthe length of the helical member between the proximal and distal ends ofthe helical member. In the deployed flange, the intermediate deflectingsection is thus located on a peripheral extremity of the deployed flangeand the flange is substantially perpendicular to the stent longitudinalaxis. Alternatively, the intermediate deflecting section may be locateddistally or proximally along the length of the helical member, so thatthe flange is angled relative to the longitudinal axis of the stent. Forexample, where the intermediate deflecting section is located betweenthe center point and the distal end of the helical member, the flange isangled toward the distal end of the large vessel stent 110, asillustrated in FIG. 29.

[0077] In the embodiment of the large vessel stent illustrated in FIGS.18-20, the length of the large vessel stent before deployment of theflanges is greater than the width of the target vessel wall, so that thedeformable sections are on either side of the target vessel, at least inpart outside of the incision in the target vessel wall. The length ofthe stent after the flanges are deployed, as illustrated in FIG. 20, issubstantially equal to the width of the target vessel wall. The lengthof the stent 110 is about 0.5 mm to about 5 mm, and the diameter isabout 4 mm to about 10 mm. The large vessel stent is preferably formedfrom stainless steel. However, other suitable materials may be used,including tantalum, titanium, and alloys thereof. The large vessel stentwall thickness is about 0.10 mm to about 0.20 mm.

[0078] The anastomotic stents of the invention may be used for a varietyof anastomosis procedures, including coronary bypass surgery. Forexample, the distal end of a dissected mammary artery can be connectedto a coronary artery, using a small vessel stent of the invention.Typically, one or more slices are made in the end of the mammary arteryin order to increase to diameter of the mammary artery to facilitate itsconnection to the outer flange of the small vessel stent. FIG. 30illustrates a heart 160 on which a coronary bypass has been performedusing the anastomotic stents of the invention. The distal end of aharvested vein graft 125 is connected to the coronary artery 161 using asmall vessel stent of the invention, and the proximal end of the graftvessel is connected to the descending aorta 162 using a large vesselstent of the invention.

[0079] In an anastomotic system using the large vessel stent incombination with the small vessel stent, the large vessel stent wouldpreferably be connected to the target vessel first, so that the lumen ofthe graft vessel would be accessible through the other end of the graftvessel, to thereby provide access for a catheter which incises andexpands the aortal wall. The small vessel stent would be connected next,because it requires no access through the lumen of the graft vessel.

[0080] Although principally discussed with respect to coronary bypasssurgery, the anastomotic stents of the invention may be used in a numberof anastomosis procedures. For example, the other types of anastomosisprocedures include, femoral-femoral bypass, vascular shunts,subclaviancarotid bypass, organ transplants, and the like.

[0081] It will be apparent from the foregoing that, while particularforms of the invention have been illustrated and described, variousmodifications can be made without departing from the spirit and scope ofthe invention. For example, those skilled in the art will recognize thatthe large and small vessel stents of the invention may be formed ofwound or bended wire, filaments and the like. Other modifications may bemade without departing from the scope of the invention.

What is claimed is:
 1. An anastomosis stent assembly for connecting oneend of a graft vessel to a target vessel, comprising a) an outer flangeconfigured to be positioned adjacent an outer surface of the targetvessel, having a body defining an opening configured to receive the endof the graft vessel; and b) an inner flange connectable to the outerflange, having a body defining an opening, and being configured to bepositioned adjacent an inner surface of the target vessel, to providefluid communication between a lumen of the graft vessel and a lumen ofthe target vessel
 2. The stent of claim 1 wherein the inner flange isconfigured to connect to the outer flange to form a channel formed atleast in part by the target and graft vessels between a lumen of thegraft vessel and a lumen of the target vessel.
 3. The stent of claim 2wherein the inner flange is configured to be insertable into an incisionin the target vessel which in part defines the channel.
 4. The stent ofclaim 3 wherein the inner flange has a folded configuration with aprofile to facilitate insertion of the flange into the target vessel,and an unfolded configuration with a profile larger than the profile ofthe folded configuration.
 5. The stent of claim 3 wherein the innerflange further includes at least one connecting member to connect to theouter flange, configured to extend through the incision in the targetvessel.
 6. The stent of claim 5 wherein the connecting member comprisesat least one prong configured to engage the outer flange and connect theinner and outer flanges together.
 7. The stent of claim 6 wherein theouter flange has at least one opening configured to receive a prong onthe inner flange.
 8. The stent of claim 7 wherein the prong receivingopening is configured to fixedly receive the prong.
 9. The stent ofclaim 1 wherein each of the inner and outer flanges further include aplurality of openings for receiving sutures for connecting the flangestogether.
 10. The stent of claim 1 wherein the inner flange isconfigured to be connected to the outer flange, so that a compressiveforce is applied to the graft vessel against the outer surface of thetarget vessel.
 11. The stent of claim 1 wherein the opening in the innerflange and the opening in the outer flange are substantially centrallylocated thereon.
 12. The stent of claim 1 wherein the inner flange has alength that is not greater than a length of the outer flange.
 13. Thestent of claim 1 wherein the inner and outer flanges are substantiallyoblong.
 14. The stent of claim 13 wherein the opening in the innerflange and the opening in the outer flange are substantially oblong. 15.The stent of claim 1 wherein at least one of the inner and outer flangeshas an arcuate shape configured to conform to the target vessel.
 16. Animplanted anastomosis stent for connecting one end of a graft vessel toa target vessel at an incision in a wall of the target vessel,comprising a) an outer flange configured to be positioned adjacent anouter surface of the target vessel, having a body defining an openingconfigured to receive the end of the graft vessel; b) a graft vesselwith an inner surface and an outer surface, extending within andeverting out of the opening of the flange body so that the graft vesselouter surface is adjacent to the flange body and the graft vessel innersurface is adjacent to an outer surface of the target vessel; and c) aninner flange having a body defining an opening, adjacent an innersurface of the target vessel and connected to the outer flange toprovide fluid communication between a lumen of the graft vessel and alumen of the target vessel.
 17. The implanted stent of claim 16 whereinthe graft vessel is further everted about the body of the outer flange.18. The implanted stent of claim 16 wherein the inner flange isconnected to the outer flange by a connecting member on the inner flangeextending through the incision in the target vessel.
 19. The implantedstent of claim 18 wherein the connecting member comprises at least oneprong extending through a wall of the graft vessel and through the outerflange body.
 20. A method of forming a vascular anastomosis between agraft vessel and a target vessel, comprising a) connecting an end of thegraft vessel to an anastomosis stent comprising i) an outer flangeconfigured to be positioned adjacent an outer surface of the targetvessel, having a body defining an opening configured to receive the endof the graft vessel; and ii) an inner flange connected to the outerflange, having a body defining an opening, and being configured to bepositioned adjacent an inner surface of the target vessel, to providefluid communication between a lumen of the graft vessel and a lumen ofthe target vessel; b) introducing the inner flange into an incision inthe target vessel; and c) connecting the graft vessel to the targetvessel by tightening the inner flange and the outer flange together. 21.The method of claim 20 wherein the inner flange further includes atleast one prong member for connecting to the outer flange, and furtherincluding the steps of, after step (a), connecting the inner flange tothe outer flange by inserting the prong member into a prong receivingopening in the outer flange so that the prong extends through a wall ofthe graft vessel.
 22. The method of claim 21 further comprising, afterstep (b), positioning the inner flange within the lumen of the targetvessel so that the prong member extends through the incision in thetarget vessel.
 23. The method of claim 20 wherein the step of connectingthe graft vessel to the target vessel further comprises the step ofcompressing the graft vessel against the outer surface of the targetvessel.
 24. The method of claim 23 wherein the step of connecting thegraft vessel to the outer flange comprises everting the graft vessel outthe opening in the outer flange body so that an inner surface of thegraft vessel is compressed against an outer surface of the targetvessel.